Functionalization of poly(glycidylmethacrylate) with iminodiacetate and imino phosphonate groups for enhanced sorption of neodymium - sorption performance and molecular modeling

Polyglycidyl methacrylate (PGMA, obtained by dispersion polymerization method) can be successfully functionalized to improve the sorption of Nd(III). Pristine PGMA is first modified by amination (N-PGMA), before grafting amino-alkylcarboxylate and amino-alkylphosphonic ligands to produce A-PGMA and P-PGMA, respectively. These materials are characterized by CHNP, FTIR-spectrometry, XRD, TG-TDA and pH zpc. Following that, the Nd(III) sorption properties are compared. At optimum pH: 4.5–5.0, the sorbents can be ranked according the series: P-PGMA (0.645 mmol Nd g −1 ) < A-PGMA (0.736 mmol Nd g −1 ) (vs. 0.304 mmol Nd g −1 for N-PGMA). Sorption capacities increase with temperature. Sorption isotherms are modeled using the Langmuir equation. Equilibrium is reached within 180 min. Uptake kinetics are controlled by the resistance to intraparticle diffusion (fitted by the Crank equation). The sorption is endothermic, spontaneous and followed by an increase of the entropy of the system. Elution and regeneration are carried out using HNO 3 solutions achieving >91%. Theoretical DFT calculation (molecular modeling) and FTIR spectroscopy, the interactions of Nd(III) with reactive functional groups (carboxyl, hydroxyl, amine and phosphonate groups) are characterized. Finally, the sorbents are tested on pre-treated leachate of Egyptian monazite: REEs' sorption performances are correlated with their intrinsic properties and compared for the two sorbents.